Block-signal system.



L. A. HAWKINS.

'BLOUK SIGNAL SYSTEM.

APPLICATION FILED JULY 19, 1904'.

949,322 Patented Feb. 15, 1910.

witnesseg Inventor. AZM Laurence H l lawkins.

' home and distant signals.

UNITED OFFICE.

LAURENCE A. HAWKINS, 01? SCHENECTADY, NEW YORK ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION 'OF NEW YORK.

BLOCK-SIGNAL SYSTEM.

Specification of Letters Patent.

Patented Feb. 15, 1910.

To all whom it may concern:

Be it known that I, LAURENCE. A. HAW- KIN s, a citizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Blocktrain is in a block, the home signal at the entrance to that block and the distant signal at the entrance to the preceding block should be at danger. These two si als are on different semaphore posts, an the length of a block apart.

When direct current is employed as the source for the track circuits and signal-controlling relays, two methods are in common use for securing the proper operation of the In one of these systems a relay at the entrance to a block controls the circuit of the operating mechanism for the home si al at that point and also the' circuit for tile operating mechanism of the distant signal at the entrance to the preceding block. With this arrangement it is necessary that the circuit of the operating mechanism forthe distant signal should extend the length of the block. In

another arrangement the necessity for these circuits, each one extending the length of a block, is done away with by the use of a polarized relay for controlling the circuit of the operating mechanism of the distant signal. By theuse of the polarized relay, the relays for the operating'mechanisms for all the signals may be laced at the same points at which the signa s themselves are placed. It is evident that this latter system possesses a number of advantages over the former,

both as regards cost of installation and maintenance.

WVh'en alternating current is employed as the source for o crating the signal mechanisms, it is evi ent that a olarized relay cannot be used, such relays being suited to direct current only. In certain cases alternating current has several advantages over direct current for use in such systems. In

the case of an electric railway where the rails act as return conductor for the trolley current, the current in the rails interferes with the proper operation of the signal relays when direct current is used in the track circuit. When alternating current is used, it is possible to emplo relays for the signals, which are not ai'ected by direct current. In a Patent No. 845,220, issued to F. B. Corey, February 26, 1907, is disclosed a system in which alternatin current may be used with its attendant advantages, and in which all the advantages of the direct current system without wires may be obtained. This system consists in the employment of two relays, one for operating the home signals, responsive to a flow of current, and the other being responsive to a reversal of current in the block, relative to the source. The first of these relays, controlling the home signals, is of the usual type, but is screened from direct cifrrents by being connected to the rails through a transformer. The second relay, which operates the distant signals, is of the wattmetcr type, having one member excited by alternating current taken directly from the source and the other member excited by alternating current taken from the block, which is connected to the .tive to that in the source, and the direction of torque of the wattmeter relay, controlling the distant signal at the entrance of the block, is reversed. Thus, by using a transformer with one relay, and a relay of the wattmeter type corresponding to the usual polarized relay, a system similar to the direct current is obtained.

My invention in one aspect consists in an improvement in the above described system, and comprises a novel arrangement 0 a rela and its circuit, such that a single relay talies the place of both relays used in the above system. I accomplish this by providing a single relayv of the wattmeter type arranged w en moved in'one direction to close the circuit for one signal, and when moved in the other direction. to close the circuit df both signals; while when deiinergized, the circuits of both signals are 0 en. With this arrangement, one relay aud ts transformer mayl be omitted, thereby simplifying the lays are connected directly between the line system and reducing the expense. Further- 'wire a and the return'rail. I

more, not only is the relay unaffected by direct current 1n the rails, but it is also untained with a simple relay connected to affected by. an alternating current of dif-- ferent frequency,a result that cannot be 01bt 1e track through a transformer.

In its broader aspect my invention is not limited to a systememploying alternatingcurrent in the track circuit, but consists in the combination with home and distant signals and their operating mechanisms, of'a relay movable in either direction and controlling the operating mechanisms; the relay being so arranged that when it is moved in one direction it energizes the operating mechanisms for both signals, and in the other direction the mechanism for the home signal only, together wit-h means operatively connected to the home signal of the following block forv reversing the connections from v the rails of the block to the source of current. 4

My invention will best be understood by reference to the accompanying drawing,

which shows 'di'agrammaticall the relay and its circuits arranged in accor' ance with my invention.

In the drawing, A A A represent three blocks of a railway. It will be seen that only one of the rails is divided into blocks,

' the other rail being continuous throughout 4 all the blocks so as to serve as return con-' 35 ductor for the power current.

or represents a line-wire connected to a source of alternating current and connected to the continuous r'ail through the primaries ofthe transformers E, E. \Vith this arrangement, the continuous rail acts as return conductor for the alternating current also, but a separate-return conductor may be employed if preferred.

S and S represent two semaphore posts at' the entrance to blocks A and A respectively. Each post carries a home si nal H and a distant signal D,,.the'signals block A being the home signalH'on semaphore post S, and the distant signal D on semaphore post S. Thus, whena car is -in block A, as indicated by, C, signals Hand D should be at danger, as shown; while signal H is at safety position, since no car is in block- A.

The secondaries of transformers E and E are connected to the blocks A and A" through reversing switchesK and K. By means of these switches the phase of the currents in the rail circuitsrelative to the current in line-wire a may be reversed. To the other ends of the blocks are connected. on'e winding of the relays J J, whichare shown The other, or stationary, windings of the reto the phase of the current in line-Wire a,

of both magnet windings 2' and j.

for the cuits of both magnet windings are open.

This is the position which the contact member assumes'either by'gra-vityor aspring when ther'elay is deenergized. nThe magnet windings z' and j control the rods h and (Z, respectively, which are the operating rods for the home signal H and distant signal D, respectively. The connections between these rods and the signals are omitted for the sake .of simplicity. The rod it also controls the phase changing or reversing switch K. The phase-changing switch K controls the phase of the current in the block A, relative as will be readily seen from tracing out the circuits of this switch. In other words, the switch K controls the relative phases of the currents in the two members of the relay J. The operation 'is then as follows: with a car C in the block A the armature of relay J is short-circuited, the'relay is consequently denergized and assumes the position shown in the drawing, thereby opening the circuits Both signals H and D go to danger by gravity, indi- .cating the presence of the car in the block.

As signal H goes to danger rod h is moved downward to move switch K to the position shown. The relay .J has its movable winding energized with current in a direction, relative to that in linewire a, determined by the position of switch K. The direction of current is such as to move contact memher I to the right, thereby closing the circuit of magnet coil 71, while leaving the circuit of magnet coil y" open. Home signal H is consequently drawn to safety position by magnet winding 2', while the distant sigi When car C 5 circuits of both windings i and j, and signals H and D will consequently be drawn to safety, indicating that both blocks A and A are clear.

Evidently, direct current in the track circuit cannot affect the operation of the signals, since direct current in the movable winding-and alternating current in the stationary windin would produce a torque alternating in irection. The same would be the case with alternating current in the track circuit of a diflerent frequency from that of the current in the signal circuit.

Although I have shown my invention as applied to a signal system employing alternating-current in the track circuit, it will be understood that in some of its aspects my invention is equally applicable to directcurrent systems.

It will be understood that I'have shown the operating mechanisms for the signals diagrammatically, and that any well known form of operating mechanism may be used in the arrangement that I have shown and described.

f Accordingly, I do not desire to limit myself to the particular construction and arrangement of parts here shown, but I aim in the appended claims to cover all modifications which are within the scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. In a block signal system, home and distant signals at the entrance to a block, operating mechanisms therefor, a relay movable in either direction and controlling said operating mechanism, said relay being arranged when moved in one direction to energize the operating mechanism for both signals and in the other direction the mechanism for the home. signal only, and means operatively connected to the home signal of 'the following block for reversing the direction of movement of said relay.

2. In a block signal system, home and distant signalsat the entrance to a block, electroresponsive operatin mechanisms therefor, a relay movable in elther direction, switch contacts controlled by said relay and arranged to close the circuits of both mechanisms when said relay is moved in one direction and of the mechanism for the home signal onlywhen said relay is moved in the other direction, and means 0 eratively con nected to the home signal 0 the following block for reversingthe direction of movement of said relay.

'3. In a. block signal system, a source of current connected to one end of'a: block, a relay connected'to the other end of the block comprising an armature having an off position and. movable in either direction from said off position upon a reversal of current in the b ock relative to the. source, means for reversing the current in the block relative to the source, and si a1 mechanism for the block controlled by the relay and indebted-to give three distinct indications corresponding to the three positions of the relay armature.

4. In a block signal system having home and distant signals, a source of current connected to one end of a block, means controlled by the home signal of the followin block for reversing the connections of said source to said block, a relay connected to the other end of the block and movable in opposite directions upon a reversal ofcurrcnt in the block relative to the source, and home and distant signals controlled by said relay. 5. In a block signal system, a source of alternating current connected to a block, means for reversing the connections of said source to the block, a relay having two windings relatively movable in either direction, one of said windings being connected to said source and the other to said block, a si nal arranged and connected to be operated by the movement of said relay in either direction, and a secondsignal arranged and connected to be operated by the mqvement of said relay in one direction on 6. Ina block signal system, a source of current connected to one end of a block, a relay connected to the other end of the block comprising an armature havi an off position and movable. in either direction from said off osition upon a reversal of current in the block relative to the source, means controlled by a train in the followin block for reversing the current inthe bloc relative to the source, asignal for the block adapted to give three distinct indications corresponding to the three positions of the relay armature,and electrico erating means for the signal controlled by tlie'relay armature.

7. In a block signal system having electrically-o erated home and distant signals, a source 0 alternating current connected to one end of a block, means controlled by the home signal of the following block for reversing the connections of said source to said block, a relay having two relatively movable windings, one connected to the other end of said block and the other to said source, and.

means operatively connected to said relay for closing the circuit of the operating mechanism of the home signal for said block upon a movement of said relay in either direction and for closin the circuit of the operating mechanism 0 a distant signal upon a movement of said relay inone direction.

ism for the home signal only, and means operatively connected to the home signal of the following block for reversing the direction of movement of said relay.

9. In a block signal system,-homeand dis-. tant signals at the entrance to a block, electro-responsive operating mechanisms therefor, a selective relay movable in either direc- 1 tion, switch contacts controlled by said relay and arranged to close the circuits. of both mechanisms when said relay is moved in one direction and of the mechanism for the home signal only when said relay. is'moved in the other direction, and means operatively connectedto the home signal of the following block for reversing the direction of movement ofsaid relay.

10. In a block signal system, signals for the several blocks, operating mechanisms therefor adapted to cause the signals to give three distinct indications, asource of alternating current connected to the rails of each block, a relay for each block having two co operating windings, one supplied from the track rails and the other supplied with altrolled by at-rain in theblock ahead for controlling the relative phases of the currents in the two windings of'the relay.

l1. Ina block signal system, signals for movable in either.

the several blocks, operating mechanisms therefor adapted to cause the signals to -.giv'e three distinct indications, a source of alternating current connected to the rails of each block, a relay for each block having two cooperating windings, one supplied irom the track rails and the other supplied with v alternating current independently of the rail circuit, said relay being movable in either directionfrom ofl position according to the relative phases of the currents in its windings and being provided with contacts controlling the operating mechanism for causing the signal for that blockto give different indicatlons according to the direction of movement of the relay, and means controlled by a train in .the block ahead for controlling the relative phases of the currents in the two windings of'the relay reversing the phase'of thecurrentsupplied by said source to the track rails.

12.In a railway block signaling system, having av closed alternating-current track circuit for controlling the signals, a plurality of block sections, j distantandhome signals for each block, a single relay controlling said distant and home signals, controlled partly by said track circuit and partly byan external circuit,: and. means whereby one of the signal mechanisms of a distant block may affect the track circuit so as to reversely-actuate said relay.

In witness whereof I have hereunto set my hand this 18th day of July, 1904.

LAURENCE vA. HAWKINS.

Witnessesf BENJAMIN B. HULL, HELEN ORFORD. 

